Sharp Marine Inversion

A great picture from Scott Withers showed up on our Facebook page (fox12weather…”like” it!) today.  The location is Lookout Mountain is on the east side of Mt. Hood.  You can clearly see the inversion over the lower valleys; cooler nighttime air drains down into the lowest elevations while warm air remains above.  What you see here is not the marine inversion west of the mountains, but just overnight cooling.  Nonetheless, it shows the cooler/denser air down below trapping the smoke.

Check out the westside temps:  70 here in Portland, 61 at 1,100′ or so at Brightwood, but 71 up at Timberline Lodge at 6,000′!  Timberline has dropped less than 10 degrees since Sunday, while down in the valley it’s dropped 26 degrees (Brightwood).  The layer of cool air was about 3,000′ thick today, and will probably thin slightly tomorrow.  The marine inversion goes away Thursday and Friday with much cooler air moving in at the higher elevations.

Speaking of cooler, both the GFS and ECMWF show some sort of “real” rain arriving over the Pacific Northwest Saturday night or Sunday.  If so, it’ll be the first significant rain since late July.  It will have been exactly two months since the big soaking on the 17th of July.

Chief Meteorologist Mark Nelsen

43 Responses to Sharp Marine Inversion

  1. boringlarry says:

    …interesting day up here; got back from town around 2 and a west wind has been blowing non stop since then averaging around 8 mph at 10th foot level…….and temp has dropped from 67 to 54 since about 4:30, and can now see a wall of clouds banking against and starting to spill over the ridges to our west…from clear lake cg….not a good night for sitting around a nice crackling fire…

  2. EA_TTD says:

    And then there’s this…Cook, Minnesota forecast for tonight. The upper Midwest is getting a very early taste of winter….

    Tonight-A slight chance of rain, snow, and sleet before 10pm. Widespread frost after 1am. Otherwise, mostly cloudy, then gradually becoming clear, with a low around 20. North wind between 5 and 10 mph becoming calm. Chance of precipitation is 20%.

  3. bgmike says:

    UW models giving us more than half an inch of rain Saturday night into Sunday.

  4. bgb41 says:

    18Z GFS – Do we have one more hot spell in us this year??

    This run says yes!!!!!!!!!!!

  5. heres a seattle blog post about the inversion and smoke with the fires up there. with some pretty cool timelapse videos.

  6. Jbpdx says:

    If it does rain, depending on how much and widespread, that should begin the process of finishing off Oregon’s $2 billion wine crop for this year.

    • Boydo3 N. Albany 500' says:

      I really don’t think we’ll get enough rain to cause a problem with the grapes. What would have hurt even more would be if we hadn’t ever gotten the heat we finished with. But if it started raining and didn’t quit right away…….

    • Pete says:

      The crop isn’t worth anything near $2 billion. In 2010, for instance, it was valued at $63.2 million. Perhaps you’re thinking of the value of all economic activity associated with the Oregon wine industry, including direct and indirect impacts?That’s north of $2 billion, but it could rain for 40 days and 40 nights and the vast majority of those impacts would not vanish. (Source:

      Anyway, a day or two of rain should be of minor consequence….

    • pdxgeologist says:

      I spoke to a friend of mine a week or so ago who owns 2 major winerys in the Dundee area. His main concern at that time was that the prolonged heat we were having had the potential to burn the grapes because the vintners had been heavily deleafing the vines to promote faster ripening back when we were stuck in the June / July gloom (like most other crops, grapes are several weeks behind this year). He also said that they were very concerned about the late harvest last year, but ended up with a great vintage.

    • Boydo3 N. Albany 500' says:

      Yeah, I have a neighbor who has a small winery, Sringhill Winery, and their big concern is that people just aren’t buying wine like they did a few years ago! BTW Springhill produces an excellent pinot noir!

    • Punxsutawney (aka HIOPHIL) at work by Sunset High elev ~280' says:

      I can’t speak for the wine industry, but the warm dry weather since late July was just what my table grapes needed. They are very close to being fully ripe and look great! I plan on starting to harvest this weekend.

      Extended humid wet weather would be my biggest worry but I’m doubtful of that. I don’t want the mold problem that plagued me last September.

      A day’s rain at this point will hardly penetrate the sun baked (51 days without rain) soil here.

  7. Anthony Bertolo - Hillsboro says:

    It’s that time of year again. Time to start frequenting the blog. Didn’t post much all summer because, well, there wasn’t much to post about.

    But I’m back.

  8. pappoose in scappoose says:

    OK, the Fall rains are about to begin, and the RADAR IS DOWN…AAAIIIEEE!!!

    National Weather Service Portland or
    900 am PDT Wednesday Sep 14 2011

    Long term…the real feature of interest for the forecast period is a
    system that is modeled to affect the Pacific northwest over the weekend. Todays model runs have trended significantly wetter with this system. Both the 00z GFS and European model (ecmwf) are showing a good batch of precipitation for
    Sat into early sun. The GFS is indicating that a precipitable water
    plume in excess of 1.50 inches will be pointed at our coast. There
    are still plenty of details that need to be worked out over the next
    couple of days…but it is looking more likely that a large portion
    of our County Warning Area will have the potential to see measurable rain for the first time in a few weeks.A longwave upper level trough will continue to move through the Pacific northwest on Sunday. Model agreement is pretty good
    that a period of ridging will develop on Monday behind the departing trough. However…the ridging looks like it will be short lived. Model agreement is poor beyond Monday…but it appears that there will be another couple of systems that may threaten to bring precipitation to the region next week. Jfp

  9. Timmy_Supercell (Klamath Falls @ 4200') says:

    Later in the week at 4,000’+ we will be dropping into the low-mid 70’s. Weather is really going to make a change, I’ve been 80-90F range for the last two months with only a few 70’s thrown in. This time its ‘bye bye’ 80-90F!

  10. Karl Bonner says:

    It’s always fun to see an inversion in the warmer months of the year: instead of a cool pool east of the Cascades and east Gorge wind, you get a cool marine “pool” on the west side and a powerful west wind.

  11. bgb41 says:

    9/13/2011 Oregon (All) Temperature Summary

    High:97 at WARM SPRINGS BAS(1563 ft) & ILLINOIS VALLEY(1389 ft) & DW7799 Heppner(2103 ft) & DW1597 Troy(1612 ft)
    Low: 69 at Rufus(185 ft)

    High:55 at YACHTS Yachats(74 ft)
    Low: 35 at CRAZYMAN FLAT (6100 ft )

    Largest Diurnal Change: 51 degrees
    FOSTER FLAT (87/36 ) (5000 ft )

    Heaviest Rainfall:
    0.57″ at KELSEY BUTTE(5187ft)
    0.51″ at CROW FLAT(5130ft)

  12. Mike near Clackamas Town Center says:

    The cascades needs the rain very badly to help put out fires 🙂

  13. Mark Nelsen says:

    A repost from PaulB/Eugene…didn’t want it to get lost in the previous post:

    Here is a compilation of winter 11-12 forecasts that I have seen (from blog on Accuweather)…winter-outlook/…er-forecast-new….er&tid=6241…11-2012-outlook…tlook-2012.html (from Snowstorms, AccuWeather member)…-2011=2012.html

    • bgb41 says:

      Interesting video. Seems like it is entirely possible for us to have a drier than normal winter this year due to increased blocking interrupting the jet. We shall see. Thanks for posting this.

    • Timmy_Supercell (Klamath Falls @ 4200') says:

      I knew this winter wasn’t right for lots of snow. Interesting post, Paul! Definitely interesting

    • Timmy_Supercell (Klamath Falls @ 4200') says:

      oops “wasn’t” wasn’t the right word!

      Typos happen all the time, right?

      I meant ‘was’

    • Chuck on Mt Scott says:

      Of course its going to be drier. This is the first year I vowed to start skiing again, since my kids were born 9 yrs ago.

    • Karl Bonner says:

      The only part I don’t get are the nitpicky predictions for November vs December vs January, etc. It just sounds too much like a Farmer’s Almanac forecast.

  14. Timmy_Supercell (Klamath Falls @ 4200') says:

    Wow I just logged on at 10:52 after a few hours of playing games and at this minute is when Mark made the post. We must share minds….

  15. Timmy_Supercell (Klamath Falls @ 4200') says:


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